JPS62297120A - Molding tool for lens - Google Patents

Abstract

PURPOSE:To remarkably easily manufacture a contact lens of an excellent quality in a short period of time by a method wherein a male and a female molding members are combined through a abutting part and a spacer to control the thickness of a lens to the outer peripheral portions of the molding parts of both the molding members. CONSTITUTION:The molding part 2 of a male molding member 4 and the molding part 6 of a female molding member 8 form a vertically shiftable fitting structure. When both the molding members 4 and 8 perfectly contact through a spacer 9 with each other, a certain volume of polymeric composition liquid is filled in a gap for molding a lens. The molding tool is heated in a constant temperature bath in accordance with a temperature raising program. Since the volume of the polymeric composition liquid decreases due to the shrinkage on polymerization, a force acts in the direction so as to draw near a molding surface 1 and a molding surface 5. The spacer 9 shows the flexibility so as to decrease its thickness as both the molding members 4 and 8 draw near, resulting in absorbing the shrinkage on polymerization in the direction of the thickness of a lens. On the other hand, the abutting part 10 formed on the molding member 8 correctly determines the thickness of the lens and prevents said thickness from becoming locally ununiform. Consequently, a contact lens without sinkmarks, flashes and the like can be easily manufactured with no machining at all.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a mold used in cast polymerization, which is a method for manufacturing lenses, and more specifically relates to a mold used in cast polymerization, which is a method for manufacturing lenses. The present invention relates to a soft contact lens mold that is legally suitable for manufacturing soft contact lenses with a water content of 60% or more.

[Conventional technology] Conventionally, contact lenses have been mainly manufactured by subjecting a polymeric composition having desired physical properties to mechanical processing such as cutting and polishing (hereinafter referred to as the cutting and polishing method). A contact lens with good optical performance can be produced, and its shape can be designed relatively freely as needed.

In addition, as another Vm method for producing contact lenses, there is a method called a spin casting method in which a contact lens is obtained by solidifying the m mixture on a rotating mold. The spin casting method is a process in which a specific contact lens is formed by carefully controlling a number of factors such as the viscosity of the polymer solution, surface tension, amount used, mold shape, rotation speed, surface condition, etc. This method is expected to improve productivity compared to cutting and polishing methods, and is advantageous for manufacturing thin-walled contact lenses.

Furthermore, as another method for manufacturing contact lenses, the cast polymerization method is a manufacturing method in which the polymer solution is positively combined in a mold with a predetermined optical surface to form a contact lens shape, and is highly productive and easy to implement. It has the advantage of being easy to use.

[Problem to be solved by the invention 1 However, as is well known, the cutting and polishing method is a method in which each lens is cut out from a material one by one and finished by polishing, so it inevitably requires a large number of manufacturing steps. However, there were problems such as poor productivity. In addition, the cutting and polishing method requires advanced machining techniques and has the disadvantage of requiring the sound of a large number of skilled workers. Furthermore, in the cutting and polishing method, the first condition is that the material be hard and capable of machining, so even if the material has excellent physical properties, there may be problems with machinability or polishability. ,
The drawback was that it could not be made into contact lenses. In particular, many soft contact lens materials with high water content are soft and have problems with machinability and abrasiveness, and lens materials have strong hygroscopicity, so they are susceptible to the effects of moisture in the air during processing. Yazuku faced the problem of always having to maintain a low-humidity environment.

Furthermore, high water content soft contact lenses produced by cutting and polishing have a disadvantage in that dirt from tear fluid tends to adhere to them due to poor surface smoothness.

On the other hand, the spin casting method requires highly sophisticated technology as it requires strict control of a large number of factors as described above, and furthermore, the materials to which it can be applied are limited to specific materials.

In addition, the concave surface of contact lenses obtained by the spin-casting method is an aspherical surface with a parabolic shape, making it impossible to obtain a true optical surface. It has the disadvantage of being difficult to set. Additionally, lenses obtained by spin-casting typically suffer from the disadvantage that final finishing around the lens is required after polymerization.

The cast polymerization method is effective as a means to solve the above-mentioned problems in the cutting h11 polishing method and the spin casting method. However, the cast polymerization method involves the problem of volumetric shrinkage called combinatorial shrinkage that occurs when the polymerizable liquid combinally solidifies. The volume shrinkage due to polymerization shrinkage of many monomers is 12
% to 22%, and this shrinkage is commonly used in contact lenses such as acrylates, methacrylates, vinylpyrrolidone, substituted
This has been a major hindrance to the cast polymerization of contact lenses from substituted vinyl monomers such as acrylamide and methacrylamide. However, when contact lenses are cast in a sealed mold, voids called sink marks may occur on the surface of the lens due to polymerization shrinkage, or cavities called voids may occur inside the lens, causing the cast product to deteriorate. It is considered inappropriate as such.

In order to solve these problems of cast polymerization, various methods have been taught so far. For example, JP-A-52-117
According to the method disclosed in Publication No. 647@, a flexible rim part is integrally disposed on one side of a set of molds, and polymerization shrinkage is absorbed by the curvature of the flexible rim part and the resulting reduction in wall thickness. . However, although this method can absorb the polymerization shrinkage that occurs when the polymer composition liquid polymerizes and solidifies, there is no control mechanism for the thickness of the lens as a result of the molding process. There is a problem with molding accuracy in that the thickness of the lens varies. In addition, since the above flexible rim component directly forms the outer peripheral part of the contact lens during cast polymerization,
This has the disadvantage that the design around the lens is limited to the shape obtained by the curvature of the rim, making it impossible to design freely. Furthermore, since the flexible rim part must be integrated with the mold, the materials that can be used as the mold are inevitably limited to flexible materials such as Plus Deck due to processing, heat, and material selection. The drawback is that there is little freedom in selecting the material for the mold, and there are inevitably limits to the hardness and heat resistance of the material required for the mold. The problem was that sufficient optical accuracy could not be obtained due to the deformation caused by the deformation. Furthermore, in order for the flexible rim to obtain sufficient curvature to absorb polymerization shrinkage, its thickness must be extremely thin, and its tip must be 0.04 m/a
Since it has to be sharpened to about 0.01 m/m, there is a problem in handling that it is easily damaged even by a slight contact.

Further, for example, according to the method disclosed in Japanese Patent Application Laid-Open No. 54-43268, a swollen soft contact lens can be manufactured by polymerizing and solidifying a combination liquid together with a solvent in a mold. However, this method uses a polymerization method using a solvent (solution polymerization method) to produce soft contact lenses.
5, lenses molded by polymerization are always limited to those containing a solvent, and the above mold does not have any i64 that absorbs polymerization shrinkage. Naturally, it has the disadvantage that it is not possible to mold non-hydrous hard contact lenses.

The present invention was made for the purpose of solving the problems in the manufacturing method of syntact lenses as described above, and more specifically, it solves the problems in the manufacturing method of contact lenses by cast polymerization, and provides excellent quality. The purpose of this invention was to manufacture soft contact lenses having the following properties easily and in a short period of time.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a method for interposing a ring-shaped spacer between a male molding member and a female molding member around the outer periphery of the molding portion of both molding members. At the same time, the lens mold is made by forming a sharpening part on opposing surfaces of the molding part outer periphery of both molding members for controlling the lens thickness when the mold is closed.

Hereinafter, the configuration of the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a partially cutaway exploded perspective view explaining the present invention in detail, and FIG. 2 is a cutaway front view showing the combined state of the molds shown in FIG. 1.

The present invention provides a male molding member 4 having a main axis for assembly in the vertical direction and having a first molding part 2 containing a first optical molding surface 1 for forming the first surface of the lens. A female molding member 8 having a second molding portion 6 having a common principal axis with the molding member 4 and including a second optical molding surface 5 for forming the second surface of the lens: a female molding member 8 as described above; .A ring-shaped spacer 9 with a common axis to the right of the main axis of the lens 8: a Tsukiate part 10 for controlling the wall thickness of the lens; It is configured. This liquid reservoir 3 can store excess polymer composition liquid, so even if the polymer composition liquid is not poured into the mold accurately, the polymer composition liquid may come into contact with the spacer and adhere or attack the spacer. There is nothing to do.

As the material of the male molded member 4, female molded member 8, and lugs 10 presented in the present invention, materials commonly used as mold materials, such as glass, metal, ceramic, and plastic, can be used. In particular, when selecting thermoplastic Plus Deck as a mold material, it is important to select a material with a heat distortion temperature 20 to 40 degrees Celsius higher than the polymerization temperature. By applying ordinary plastic molding methods such as molding or compression molding,
It has the advantage of being able to manufacture highly accurate molded parts with extremely high productivity.

Examples of such thermoplastics include high density polyethylene, polypropylene, polytetrafluoroethylene, polychlorotrifluoroethylene, polyolefin copolymers, polyacetals, polyphenylene oxides, polysulfones, polyamides, and the like.

Further, as the material of the spacer proposed in the present invention, thermoplastic plastics or rubber elastic bodies having good flexibility near the polymerization temperature can be used. Examples of such materials include low density polyethylene, ethylene-vinyl acetate copolymer, ethylene-edyl acrylate copolymer, soft vinyl chloride, ionomer resin, urethane rubber, natural rubber, isoprene rubber, butadiene rubber,
Examples include styrene-butadiene rubber, chloroprene rubber, nitrile rubber, silicone rubber, and acrylic rubber. These materials are used after being molded into a predetermined shape by a normal molding method.

In the specific example of the present invention shown in FIGS. 1 and 2,
Although the base portion 10 is integrally formed with the second molded member 8, it may be formed integrally with the first molded member 4. Further, the attachment portion is not limited to being integrated with the molded member, and may be placed separately inside or outside the spacer.

In the following box 1 or the second molded member - Tsukiate part 10 on the body
The explanation will be based on the case where .

[Function] In the lens mold according to the present invention, the male molding member 4 and the female molding member 8 are assembled along the main axis with a spacer 9 in between. The first molding part 2 and the second molding part 6 of the female molding member 8 form a vertically movable fitting structure to fill out a gap for contact lens molding that is shielded from the outside. When both molded parts 4.8 are in complete contact with each other via the spacer 9, this gap provides a volume corresponding to the predetermined shape of the contact lens.

The amount of polymer composition liquid that will be polymerized and solidified to form a contact lens is slightly larger to account for the volume of the contact lens to be molded in the second molding part 6 of the female molding member 8, as well as the amount of polymerization shrinkage and overflow R. It is dripped with a branch. Thereafter, the spacer 9 is placed on the spacer contacting part of the second molded member, and the male molded member 4 is placed on the female molded member 8 along the main axis and moved downward. At this time, the excess polymer composition liquid is gradually removed from the molding space as the male molding member 4 moves, and when both molding members 4. The liquid does not fill the void for contact lens molding. Since the liquid reservoir 3 can store excess polymerizable liquid, even if the polymerizable liquid 1 is not accurately injected into the mold, the polymerizable liquid will not come into contact with the spacer and adhere to it or attack the spacer. There's nothing to do.

The void for contact lens molding filled with the polymeric composition liquid is cut off from the outside by the first molding part 2 and the second molding part 6, as described above, so that the polymeric liquid does not come into contact with air. . By placing the mold filled with the polymerization composition liquid in this way in a constant temperature oven and heating it according to a predetermined temperature increase program, a desired contact lens can finally be molded.

When the polymerization composition liquid starts polymerization in the above-mentioned heating process, its volume decreases due to polymerization contraction. It becomes adhesive and as a result exerts a force in the direction of bringing both optical molding surfaces closer to each other. The spacer 9 according to the present invention exhibits sufficient flexibility during the polymerization process, thereby reducing its thickness as the molded members 4.8 approach each other, and absorbing polymerization shrinkage in the thickness direction of the lens.

On the other hand, the tension portion 10 formed on the second molded member 8
is set in advance to have a gap between it and the first molding member 4 corresponding to the amount of decrease in wall thickness given when the polymerization composition liquid completes polymerization, so that the wall thickness of the lens to be molded can be accurately determined. This also prevents the thickness of the molded lens from becoming partially uneven.

That is, if a partial non-uniformity of polymerization shrinkage occurs, such as a part of the polymer composition liquid shrinking earlier than other parts, the first optical molding surface 1 of the first molding member 4 will be caused by the second molding member 8. the second of
It tilts relative to the optical molding surface 5, giving the lens to be molded an uneven wall thickness, but as the polymerization shrinkage further progresses, the first molded member 4 in the portion where the shrinkage occurred first as described above Further shrinkage is restricted by contacting the strength part 10, and subsequent polymerization shrinkage proceeds in other parts where the strength part 10 is not yet in contact with the first molded member 4.

Therefore, the Tsukiate part 10 corrects the relative inclination of the first optical molding surface 1 to the second optical molding surface 5 until the polymerization shrinkage is completed, and accurately adjusts the center thickness of the lens to be molded. At the same time, local unevenness in wall thickness is prevented from occurring.

In the present invention, a load can be applied to the assembled molds. The load applied to the mold actively encourages the two molded parts to approach each other during polymerization shrinkage, making it easier to prevent sink marks, and also providing more favorable results in controlling the wall thickness using the cutout part. .

Incidentally, examples of the polymerization composition liquid used here include the following. Namely, 2-hydroxyethyl methacrylate, 2-human n-xypropyl methacrylate, 2-hydroxyethyl methacrylate, 2-human n-xypropyl methacrylate,
-Hydrophilic methacrylic acid substituted monomers such as hydroxybutyl methacrylate, glyceryl methacrylate, glycidyl methacrylate, methacrylic acid, 2- and droxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, glyceryl acrylate, glycidyl acrylate, acrylic Hydrophilic acrylic acid substituted monomers such as acids, N-vinylpyrrolidone,
Alkyl-substituted N- such as methyl-substituted N-vinylpyrrolidone
Vinylpyrrolidone, N-methylacrylamide, N,N
- N-alkyl-substituted acrylamides such as N-alkylamides such as dimedylacrylamide, N-methylmethacrylamide, N,N-dimeblummethacrylamide, or N-
Hydrophilic monomers such as alkyl-substituted methacrylamide or hydrophobic methacrylic acid-substituted monomers such as methyl methacrylate and ethyl methacrylate are used as the product; methyl methacrylate, ethyl methacrylate, n-methacrylate
Butyl, 1so-butyl methacrylate, t methacrylate
Hydrophobic methacrylic acid substituted monomers such as ert, -butyl, n-propyl methacrylate, 1so-propyl methacrylate, lauryl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, methylbenzyl methacrylate, isobornyl methacrylate, methyl acrylate, Hydrophobic acrylic acid substituted monomers such as edyl acrylate, 11n-butyl acrylate, 1so-butyl acrylate, 1ltert, -butyl acrylate, n-butyl acrylate, viiso-propyl acrylate, cyclohegycyl acrylate, benzyl acrylate, Methacrylic M-substituted monomers containing silicon such as trimethylsilyl methacrylate, trimethylsiloxanyl methacrylate, tris-trimethylsiloxanylsilyl-propyl methacrylate, trimethylsilyl acrylate, trimethylsiloxanyl silylate, tris-trimethylsiloxanylsilyl-propyl acrylate, etc. Acrylic acid-substituted monomers with silicone, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, polynibrene gelicold dimethacrylate, trimebrolpropane trimethacrylate, vinyl Polyfunctional crosslinking agents such as methacrylate, allyl methacrylate, triallyl isocyanurate, vinyl acrylate, and divinylbenzene are used as subcomponents; furthermore, 7zobisinbutylnitrile, azobisdimethylvaleronitrile, benzoyl peroxide, ditert peroxide, - A mixed solution containing an appropriate amount of a polymerization initiator such as butyl or lauroyl peroxide can be mentioned.

In the embodiment shown in Figures 1 and 2 of the mold according to the invention, the first optical molding surface 1 is substantially convex and the first The second optical shaping surface 5 needs to be substantially concave, but when the first optical shaping surface 11 is substantially concave, as in the other embodiment shown in FIG. It is also within the scope of the invention that optical shaping surface 15 is substantially convex.

Further, the first optical molding surface 1 and the second optical molding surface 5 of the f1 male molding member 4.8 according to the present invention can be fully adapted to a contact lens designed by a combination of spherical surfaces, but if necessary, The present invention is not limited in any way to a design in which one or both of the surfaces are made of aspherical surfaces.

[Example] Hereinafter, the present invention will be explained in more detail based on Examples.

Embodiment 1 FIG. 1 is a partially cutaway exploded perspective view showing an embodiment of the present invention, and FIG. 2 is a cutaway front view of the embodiment shown in FIG. In this embodiment, the male molded member 4 and the female molded member 8 having the molded body 10 are manufactured by injection compression molding of Bolibu O pyrene. Spacer 9 was manufactured by injection molding ethylene-ethyl acrylate copolymer: b. First molded part 2 of male molded member 4
is the radius of curvature 8. OO±(It has a cylindrical shape with a diameter of 8.5nun with the first optical molding surface 1 of 1,005 mm at the right end.The second molding part 6 of the female molding member 8 has a radius of curvature of 8.4
It has a cylindrical shape with an inner diameter of 8.5 mm and has a second optical molding surface 5 of 7±0,005 mm at the bottom, and has a liquid reservoir 3 to prevent excess polymer composition liquid from coming into contact with the spacer 9. There is. Also, spacer 9 is 3.00±0, OQ5
It has a flat ring shape with a uniform wall thickness of am.

In this example, methyl methacrylate-1-100fl
! A polymeric composition liquid consisting of fa part, 1 to 1 hanging part of ethylene glycol dimethacrylic acid, and 0.21 part of azobisisobutyronitrile was added to the second molding part 6 of the female molding member 8 by 0.2%.
mx was dropped, a spacer 9 was installed on the spacer installation surface 7 of the female molded member 8, and the Mt molded member 4 was assembled along the main axis. At this time, the gap between the male molded member 4 and the contact member 10 was 0.02 mm.

A load of 500 grams was placed on the top of the mold prepared in this way, and the mold was placed in a thermostat with hot air circulation.
Heated at 90° C. for 2 hours and 6 hours. After heating, the mold was cooled to room temperature and then disassembled, and the molded contact lens was taken out.

There were no voids or voids on the surface or inside of the obtained contact lens, and no formation of paris around the lens. The base curve of this lens is 8.00±0,01nn+, and the radius of curvature of the front curve is 8.47±0.011.
It was 111. Also, the size of this lens is 8.5m
i, and the center wall thickness is 0.155 mm to 0.165 mm.
1111. Edge thickness is 0.195mm to 0.205m
It was m. When the refractive power of the molded contact lens was measured using a lens meter, it was -3,00±
It has a refractive power of 0.03 dio/tree, llA
The detected coronavirus was also good.

Embodiment 2 FIG. 3 is a longitudinal sectional front view showing a second embodiment according to the present invention. The male molded member 14 and the female molded member 18 are provided with a V [v] by machining stainless steel, and the lugs 20 are integrally formed with the male molded member 14. Further, the spacer 19 is made by injection molding low density polyethylene.

The first molded part 12 of this embodiment has a radius of curvature of 7.60±0.0.
The first optical molding part 11 is made of a concave spherical surface of 0.05 mm and has a cylindrical shape with a diameter of a and amm, and the second molding part 1B has a radius of curvature of 7.80±0. The liquid reservoir 13 has a cylindrical shape with an inner diameter of 8.8 mm and has a second optical molding surface 15 made of a convex spherical surface of 3.0 mm.
have. Also, spacer 19 is 5.00±o,
It has a flat ring shape with a uniform wall thickness of oosmm.

The polymerization composition used in this example was a mixture of 40 mm parts of tris-trimethylsiloxanylsilylpropyl methacrylate, 60 parts by weight of ethyl methacrylate, 2 parts by weight of triethylene glycol dimethacrylate, and 0.5 parts by weight of azobisdimethylvaleronitrile. Consists of liquid.

A polymer composition solution was injected and a mold was assembled in the same manner as in Example 1. The gap between the female molded part 18 and the contact member 20 was 0.025 mm to 0.035 mn+. The mold thus prepared was placed in a constant temperature bath at 40'C.
After polymerization was carried out by heating at 60°C for 4 hours and at 80°C for 5r1 for 8 hours, the mold was cooled to room temperature, the mold was disassembled, and the molded contact lens was taken out.

The molded contact lens has no external defects such as sink marks or cracks, and the radius of curvature of the base curve is 7.80±0.
．． It had a front curve of 0.01 mm, a radius of curvature of 7.60±0.01 mm, and a size of 8.8 mm. Also, the center thickness of this lens is 0.200++ m or 0.20 m.
5n+m, and the deviation in thickness was within 0.01 mm at maximum. The refractive power of this lens is +2.00±0.
It had 0.031 iopters.

Embodiment 3 FIG. 4 is a longitudinal sectional front view showing a third embodiment of the present invention. The male molded member 24 and the female molded member 28 of this embodiment are made by injection molding of Boric L1 trifluoroethylene, and the molded part 30 is formed integrally with the female molded member 28. The spacer 29 is made by injection molding an ionomer resin obtained by crosslinking an ethylene-acrylic acid copolymer with metal ions.

The first molded portion 21 of the male molded member 22 has a radius of curvature of 5.93.
It has a cylindrical shape with a diameter of 10.0 mm and has a first optical molding surface made of a convex spherical surface of ±0.0 in+m, and the second molding part 26 of the female molding member 28 has a radius of curvature of 6.32 ± 0.0.
It has a cylindrical shape with an inner diameter of 10.0 mm and a second optical molding surface 25 made of a 1 mm concave spherical surface, and has a liquid reservoir 23 . Further, the spacer has an O-ring shape with a thickness of 1.995 mm to 2.005 mm.

881 parts of 2-hydroxyl methacrylate, 10 tum parts of methyl methacrylate, 1 mm part of ethylene glycol dimethacrylate, 1.5 parts of methacrylic acid,
A polymer composition containing azobisisobutyro and tolyl 0.2 double sides was injected in the same manner as in Example 1. The gap between the molding member 30 and the male molding member 24 created when the molds were assembled was 0.02 ml/g.

A load of 700 grams was placed on the top of the combined mold, and the temperature was 80°C for 10 hours at 40°C and 4 hours at 60°C.
After heating at ℃ for 4 hours, the mold was disassembled and the molded contact lens was taken out.

The molded lens has no sink marks or cracks, and has a radius of curvature of 5.
Base curve of 93±0.01mm, radius of curvature 6.32
±0.01mm front curve, 10. On+n size, and the center wall thickness was 0.125 mm to 0.135 n+m. Further, the uneven thickness of the edge of this lens was at most 0.01 mm.

Next, the obtained dry lens is immersed in physiological saline,
It was saturated and swelled to make soft contact lenses. This soft contact lens has a base curve radius of 8.
0m+a, size 13.5±0.03mm, and had a stable shape with no deformation or turbidity. The center thickness of this lens was 0.19±0.01 mm, the edge thickness was 0.32±0.011111 mm, and its refractive power was −3,00±0.08 Gaobtry. The water content of this lens was 40±0.3%.

Comparative Example 1 FIG. 5 is a longitudinal sectional front view showing a comparative example. The male molded member 34 and the female molded member 38 of this comparative example were made by injection molding polypropylene, and the spacer 39
was produced by injection molding an ethylene-ethyl acrylate copolymer. This mold does not have a mounting member for controlling wall thickness. The first molded part 32 of the male molded member 34 has a radius of curvature of 8, OO±0.01 mm.
It has a cylindrical shape with a diameter of 8.5 mm and has an optical shaper 31 at the tip. The second molding part 36 of the female molding member 38 has a second optical molding surface 35 with a radius of curvature of 8.47±0.01 mm.
It has a cylindrical shape with an inner diameter of 8.5 mm and has a bottom part.

Also, spacer 39 is 3.00±o, O05+nf
It has a flat ring shape with a uniform wall thickness f1. Note that 35 is a second optical molding surface, and 36 is a second molding part.

0.2fflf of the polymer composition liquid used in Example 1 was placed in the mold.
After pouring and assembling the mold, heating was performed in a constant temperature bath in the same manner as in Example 1. After cooling the mold to room temperature, it was disassembled and the molded contact lens was taken out.
There were no sink marks on the surface or periphery of the lens. This lens has a base curve of 8.00 + 0.02mm 1
It has a front curve of 8.47±0.02mm,
Center thickness 0.16±0.021, edge thickness maximum 0.05
The thickness was uneven as +a+e, and the variation in the thickness direction was large. Also, the refractive power of this lens is -3,00±0.0
It was a 5-day optory.

Comparative example 2 FIG. 6 is a longitudinal sectional front view showing another comparative example.

The male molded member 44 and the female molded member 48 are made of ethylene-vinyl acetate copolymer, and the first molded part 42 of the male molded member 44 is integrally formed with an annular thin-walled rim 50 around the periphery. It has a first optical surface 41. This thin rim 5
0 bends toward the center of the lens when the polymer composition liquid exhibits volumetric shrinkage during polymerization to reduce its height and absorb the polymerization shrinkage. In FIG. 6, 45 is a second optical molding surface, and 46 is a second molding part.

The outer diameter of the male molded member 44 is 1.9 mm, and the radius of curvature is 1.9 mm.
45±0.03111! If, the inner diameter of the female molded member 48 is 8.2 to 8.4+.
At nn+, the second optical member 45 has a radius of curvature of 8.55±0.05 mm.

A polymer composition liquid consisting of 98 parts by weight of methyl methacrylate, 20 parts by weight of ethylene glycol dimethacrylate, and 0.3 parts by weight of di-t-butylcyclohexyl peroxydicarbonate was poured into a 0.3 ml 2ffi molding member, and the mold was placed. After heating the combination in a constant temperature bath at 60° C. for 1.5 hours, it is cooled and the mold is disassembled.

The obtained contact lens has no sink marks or cracks, but the radius of curvature of its base curve is 7.47 ± 0.4 m.
1 m, and the center thickness was J9io, io±0.02nv, so good accuracy could not be obtained. In addition, the measurement results of the refractive power of this lens showed a significant dispersion of -1.50 to -8.50 dioptres, posing a practical problem.

Note that a digital contact gauge manufactured by NEIZ Co., Ltd. and a laser interferometer manufactured by Fuji Photo Optical Co., Ltd. were used to measure the radius of curvature. Further, a digital hide gauge manufactured by Chicroc and an optical microscope manufactured by Olympus were used to measure the center wall thickness of the lens, and a projector manufactured by Nikon Corporation was used to measure the diameter of the lens.

Example 4 In this example, the male molding member 4 and the female molding member 8 were made of polypropylene by injection molding, and were combined to form a mold as shown in FIG. Spacer 9 is ethylene-
A material manufactured by injection molding an ethyl acrylate copolymer was used. The first molding part 2 of the male molding member has a cylindrical shape with a diameter of 8.5 mm and has a first optical molding surface 1 with a radius of curvature of 5.03±0.005 mm at the tip. The second molded part 6 of the female molded member 8 has a radius of curvature of 5.80±
It has a cylindrical shape with an inner diameter of 8.5 mm and has a second optical molding surface 5 of o, oos ■ at the bottom. Also, spacer 9
has a flat ring shape with a uniform wall thickness of 3, OQ±O,005 mm.

N,N-dimethylacrylamide 52 heavy base, N,N-
Dimethyl methacrylamide 10 parts & parts, acrylic gll
A polymerizable liquid consisting of part Xfii, 34 parts by weight of cyclohexyl methacrylate, 0.2 parts by weight of ethylene glycol methacrylate, and parts of azobisisobutyronitrile o and il B was added to the second molding part 6 of the female molding member 8 described above. 0.2
11iP drop, spacer installation surface 7 of female molded member 8
A spacer 9 was installed in the spacer 9, and the male molded member 4 was assembled along the main axis. At this time, the gap between the male molded member 4 and the cutout portion 10 was 0.02 mm.

On the top of the mold prepared in this way, 5
A load of 0.00 grams was placed thereon, and the sample was placed in a hot air/ring type constant temperature bath, and maintained at 40°C for 10 hours and at 80°C for 6 hours. After cooling the mold to room temperature, the lenses were removed. next,
The obtained dry lens was immersed in physiological saline and saturated with swelling to form a soft contact lens.

This soft contact lens has a base curve radius of 8.1 mm and a diameter of 13. aim, center thickness 0.18
±0.01ml, refractive index -5.50±0.06 diopters, water content 80%, tensile strength 43ka/cm2
It had a light transmittance of 99% in saline, and no shape defects such as lens deformation, cracks, or sink marks were observed. Moreover, the surface of the lens was extremely smooth.

Example 5 In this example, the male molded member 4 shown in FIG.
A female molded member 8 having an integrally formed joint portion 10 was produced by injection molding an ethylene-vinyl alcohol copolymer, and the same spacer 9 as in Example 4 was used. The first molded part 2 of the male molded member 4 is
It has a cylindrical shape with a diameter of 8.8 mm and has a first optical molding surface 1 with a radius of curvature of 5.52±0.005111 m+ at the tip. The second molded part 6 of the female molded member 8 has a radius of curvature of 5.4
It has a cylindrical shape with an inner diameter of 8.8 mm and has a second optical molding surface 5 of 3±0.005 mm at the bottom, and has a liquid reservoir 3 on the right side for holding excess polymerizable liquid so as not to come into contact with the spacer 9. ing.

In the above mold, 60,000 parts of N,N dimethylacrylamide, 40 parts by weight of benzyl methacrylate, 1 part of acrylic
110 uffi parts, azobisdimethylvaleronitrile o
, oys overlapped portion was injected in the same manner as in Example 1.

Combined casting! A load of 700 grams was placed on top of the mold, and the lens was heated in a constant temperature bath at 40°C for 10 hours, at 60°C for 4 hours, and at 90°C for 4 hours, and then the molded lens was taken out from the mold.

The obtained dry lens is immersed in physiological saline,
Contact lenses were made by saturated swelling.

This lens has a base curve radius of 8.6 mm, a diameter of 13.6 mm, a center wall thickness of 0.20 ± 0.01 mm, a refractive index of +1.50 ± 0.06 days, a water content of 74%, and a tensile strength of 38 kg/ Cm2, light transmittance 98
%, and there were no lens deformations or shape defects such as flash or sink marks.

Example 6 FIG. 4 shows another v! provided by the present invention. FIG. The male molding member 24 and the female molding member 28 of this embodiment are made by injection molding polychlorotrifluoroethylene, and the molding member 30 is integrally formed with the female molding member.

The spacer 29 is made by injection molding an ionomer resin obtained by crosslinking an ethylene-acrylic acid copolymer with metal ions.

The first molded portion 22 of the male molded member 24 has a radius of curvature of 5.25.
The female forming member 2 has a cylindrical shape with a diameter of 8.7 mm and has a first optical forming surface 21 of ±0.01ff++++.
The second molded part 26 of No. 8 has a curvature of half (% 5.64±0.01
diameter 8.7n with second optical molding surface 25 of m1ll
It has a cylindrical shape and has a liquid reservoir 23. Further, the spacer 29 has a thickness of 1.995 mm to 2.0 mm.
It has an O-ring shape with a diameter of 0.005 mm.

, N-vinylpyrrolidone 7Sffif in the above template
1 part f, 25 parts benzyl methacrylate, 1 part tetraethylene glycol dimethacrylate 0.31ff,
Injection was carried out in the same manner as in Example 4 using a mixing liquid consisting of 0.1 part by weight of azobisisobutyronitrile.

A load of 500 grams was placed on the top of the assembled molds, and the lenses were heated in a constant temperature bath at 60°C for 10 hours, 80°C for 4 hours, and 90'C for 3 hours.The lenses were then taken out from the molds.

Next, the obtained dry lens was immersed in physiological saline and saturated and swelled to form a soft contact lens.

This lens has a base curve radius of 7.8mm, a diameter of 13.0mm, and a center thickness of 0.15±0.01mm.
Refractive power -3,34+ 0.047"
J-1 has a water content of 65%, a tensile strength of 47 kg/am2, and a light transmittance of 91% in saline, which prevents lens deformation.
No shape defects such as spots or sink marks were observed.

Example 7 In this example, the male molded member 24 and the female molded member 18 in FIG. It is formed. Spacer 29 is Example 6
A similar one was used.

The first molded portion 22 of the male molded member 24 has a radius of curvature of 5,14
Diameter 8 with first optical shape 21 of ±0.01 mm
．． It has an inner rod shape of 6 mm, and the second part of the female molded member 28
The molding part 26 has a cylindrical shape with a diameter of 8.6 mm and has a second optical molding surface 25 with a radius of curvature of 4.71±0.01 mm, and has a liquid reservoir 23 .

In the above mold, 85 parts by weight of N-vinylpyrrolidone, 15 fflim parts of rose-benzylphenyl methacrylate,
A polymerizable liquid consisting of 0.5 parts by weight of polyethylene glycol dimethacrylate and 0.3 parts of azobisisobutyronitrile was injected in the same manner as in Example 1.

A load of 700 grams was placed on the top of the combined mold, and after heating in a constant temperature bath at 60°C for 12 hours and at 90°C for 5 hours,
The lens was removed from the mold.

Next, the obtained dry lens was immersed in physiological saline and saturated and swelled to form a soft contact lens.

This lens has a base curve radius of 7.9mm, a diameter of 13.2mm, and a center thickness of 0.36±0.01mm.
Refractive power +4.62±0.05 days, water content 7
3%, tensile strength of 39 kg/Cl112, and light transmittance in saline of 98%. Furthermore, this lens had a smooth surface, and no defects in shape such as lens deformation, burrs, or sink marks were observed.

Examples 8 to 11 Polymerizable liquids having various compositions were prepared, and cast polymerization was performed according to the method of Examples 4 to 7 using the mold shown in Figure 1 or Figure 4. Soft contact lenses were manufactured by saturated dry lenses in physiological saline. Table 1 shows the physical properties of these lenses.

Comparative Example 3 After pouring 2 ml of a polymerizable liquid having the same composition as in Example 4 into a polypropylene polymerization container and sealing the top,
Polymerization and curing were carried out by heating under the same conditions as in Example 4.

When this polymer was removed from the polymerization container, it was found to be soft, and an attempt was made to cut it into a lens shape, but this was not possible.

Comparative Example 4 After pouring 2 ml of the polymerizable liquid having the composition of Example 5 into a polypropylene polymerization container and sealing the top, Example 5
It was polymerized and cured by heating under the same conditions as ``.

This m-coalescence was taken out from the polymerization container, processed into a lens shape by cutting and polishing, and then hydrated and swollen in physiological saline. The obtained soft contact lens was severely deformed, and it was impossible to measure the radius of curvature of the base curve, the diameter, the center wall thickness, and the refractive power.

Comparative Example 5 A polymerizable liquid having the composition of Example 6 was poured into a polypropylene polymerization container, the upper part of which was sealed, and then heated under the same conditions as in Example 6 to polymerize and cure. This m-coalescence was taken out from the polymerization container, processed into a lens shape by cutting and polishing, and then hydrated and swollen in physiological saline.

The base curve of the obtained soft contact lens had a radius of curvature of 7.8 mm, a diameter of 13.0 mm, and a center thickness of 0.15 mm.
The refractive index was ±0.0111111, and the refractive power was -2.87 Gaobtry. In addition, this lens has a water content of 69% and a tensile strength of 17 kg/cm2, and has sufficient physical properties of 4S7.
I couldn't. (Left below) (abbreviation) DHAANlN-dimethylacrylamide NVP N
-Vinylpyrrolidone DHH8 N,N-dimethylmethacrylamide C II
H A To cyclohexyl methacrylate Acrylic acid BzH8 Benzyl methacrylate BPHA p-benzylphenyl methacrylate Bu
HA n-Butyl methacrylate 1G Ethylene glycol dimethacrylate 3G )-lyethylene glycol dimethacrylate 4G Tetraethylene glycol dimethacrylate PG Polyethylene glycol dimethacrylate AIBN Azobisisobutyronitrile 80VN
Azobisdimethylvaleronitrile [Effects of the Invention] The contact lenses obtained by the Examples of the present invention with a rating of 1!7 all had higher molding accuracy than those shown in the Comparative Examples, and especially the variation in center thickness. It has 14 characteristics such as extremely small deviation in thickness. Further, the contact lens obtained according to the present invention does not have the problem of sink marks or the appearance of spots around the contact lens. That is,
By using the lens mold according to the present invention, the following excellent effects can be obtained.

1. Contact lenses without defects such as sink burrs can be produced extremely easily and stably without any machining.
JM can.

2. The molding precision of the molded lens is extremely high, and in particular, the variation in center thickness and edge thickness are extremely small.

It is also possible to mold 3 base curves, front curves, bevels, flange curves, peripheral shapes, etc. that are designed to have an extremely large number of beams.

4.Since the molded parts and spacers are independent, it is possible to freely select the materials for each, and the range of materials that can be used is wide.The most suitable material can be selected depending on the type of in-composition liquid and the required accuracy. You can choose.

5. Since the spacer does not come into contact with the polymerization composition liquid, the spacer material can be selected without considering problems such as dissolution and deterioration by the polymerization composition liquid.

6. It can be used for both hard contact lenses and soft contact lenses, and is not limited by the mechanical workability of the contact lens material to be molded.

7. Because the mold according to the present invention accurately follows polymerization shrinkage and can be made into soft contact lenses with a water content of 40% or more immediately after molding, soft contact lenses with excellent optical precision and mechanical properties are extremely rare. It can be manufactured with a small number of steps and with good reproducibility.

8. After molding, there is no cutting machining, so soft contact lenses with good physical properties and optical precision can be manufactured without considering the influence of the humidity environment.

Such an effect of the present invention is achieved by forming a fitting structure in the first molding part of the male molding member and the second molding part of the female molding member, thereby blocking the gap for contact lens molding from the outside. However, the polymer composition solution should not come into contact with air or excess polymer composition solution should not adhere to the surroundings of the lens, and the spacer should be made of a flexible material, so that volume shrinkage due to polymerization shrinkage should be prevented by reducing the thickness of the spacer. The lens thickness can be absorbed by bringing both molding members closer together due to decrease, and the thickness of the lens to be molded can be uniformly controlled by correcting the partial non-uniformity of the lens thickness caused by the non-uniformity of polymerization shrinkage by the Tsukiate part or the Tsukiate member. Since the molding member itself does not deform or shrink due to polymerization shrinkage, important dimensions such as the radius of curvature and diameter of the 21-tact lens to be molded do not change. This is achieved for the first time due to the unique characteristics of

[Brief explanation of the drawing]

FIG. 1 is a partially broken exploded perspective view showing a first embodiment of the present invention, FIG. 2 is a broken pressure surface view of the first embodiment, and FIG. 3 is a partially broken front view showing the second embodiment of the present invention. , FIG. 4 is a fracture pressure surface diagram showing a third embodiment according to the present invention, and FIGS. 5 and 6 are fracture pressure surface diagrams showing a comparative example. 1.11.21...first optical molding surface, 5.15.2
5...Second optical molding surface, 2.12.22...First
Molding part, 6.16.26... Second molding part, 4.14.
24...First molded member, 8.18.28...Second molded member, 9.19.29...Spacer, 3.13.
23...Liquid reservoir, 7.17.27...Spacer installation surface, 10.20.30...Tsukiate part. Applicant Hoya Co., Ltd. Agent Masayuki Asa Nen

Claims (1)

[Scope of Claims] 1. A male molded member and a female molded member are assembled with a spacer and a lugs for controlling the thickness of the lens interposed on the outer periphery of the molded parts of both molded members. A lens mold that is characterized by: 2. A patent characterized in that the male and female molding members have an optical molding surface, and the spacer has a ring shape having a common main axis with the molding member, and is located at a position separate from the optical molding surface. A lens mold according to claim 1. 3. The lens mold according to claim 1, wherein the molding member is provided with a liquid reservoir. 4. The lens mold according to claim 3, wherein the liquid reservoir is provided in a slope shape around the insertion portion of the female molding member. 5. The lens mold according to claim 1, wherein a contact portion for controlling the wall thickness of the lens is integrally formed on the outer periphery of the molding portion of the male molding member. 6. The lens mold according to claim 1, wherein a lever member for controlling the wall thickness of the lens is integrally formed on the outer periphery of the molding part of the female molding member. 7. The lens mold according to claim 1, wherein the mounting portion for controlling the wall thickness of the lens is separate from the molding member and is arranged inside or outside the spacer. 8. The lens mold according to claim 1, wherein the optical molding surface of the male molding member is a substantially convex surface, and the optical molding surface of the female molding member is a substantially concave surface. 9. The lens mold according to claim 1, wherein the optical molding surface of the male molding member is a substantially concave surface, and the optical molding surface of the female molding member is a substantially convex surface. 10. The lens mold according to claim 1, wherein the spacer component is made of a thermoplastic material or a rubber elastic body.